Java tutorial
/* =========================================================== * JFreeChart : a free chart library for the Java(tm) platform * =========================================================== * * (C) Copyright 2000-2017, by Object Refinery Limited and Contributors. * * Project Info: http://www.jfree.org/jfreechart/index.html * * This library is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation; either version 2.1 of the License, or * (at your option) any later version. * * This library is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public * License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, * USA. * * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. * Other names may be trademarks of their respective owners.] * * --------- * Args.java * --------- * (C) Copyright 2011-2017, by Object Refinery Limited. * * Original Author: David Gilbert (for Object Refinery Limited); * Contributor(s): -; */ package org.jfree.chart.util; /** * A utility class for checking method arguments. */ public class Args { /** * Throws an {@code IllegalArgumentException} if the supplied * {@code param} is {@code null}. * * @param param the parameter to check ({@code null} permitted). * @param name the name of the parameter (to use in the exception message * if {@code param} is {@code null}). * * @throws IllegalArgumentException if {@code param} is * {@code null}. */ public static void nullNotPermitted(Object param, String name) { if (param == null) { throw new IllegalArgumentException("Null '" + name + "' argument."); } } /** * Throws an {@code IllegalArgumentException} if {@code value} is negative. * * @param value the value. * @param name the parameter name (for use in the exception message). */ public static void requireNonNegative(int value, String name) { if (value < 0) { throw new IllegalArgumentException("Require '" + name + "' (" + value + ") to be non-negative."); } } /** * Checks that the value falls within the specified range and, if it does * not, throws an {@code IllegalArgumentException}. * * @param value the value. * @param name the parameter name. * @param lowerBound the lower bound of the permitted range. * @param upperBound the upper bound fo the permitted range. */ public static void requireInRange(int value, String name, int lowerBound, int upperBound) { if (value < lowerBound) { throw new IllegalArgumentException("Require '" + name + "' (" + value + ") to be in the range " + lowerBound + " to " + upperBound); } } }